A line array of speakers is a group of often similarly sized speakers positioned adjacent to one another to optimize a sound level output over a larger coverage area. Line array speaker systems are often used in large venues, such as auditoriums and concert halls, where high sound level is projected over a wide coverage area. Line array speakers provide increased directivity at various frequencies. Providing increased directivity at various frequencies extends the near-field coverage area because the coverage distance from the near field to the far field transition zone is increased with frequency. The ability of line array speaker systems to increase near field extension is known. For this reason, line arrays offer significant advantages over traditional multi-box sound systems and are often used for large venues.
To achieve a desired sound level over a desired coverage area, line arrays are strategically positioned in various places, at varying heights and angles, throughout a venue. The positioning of the line arrays is determined using equations that anticipate the performance of differently sized speakers based upon their arrangement relative to one another. The specific height of a line array, and the angle and spacing between the speakers in the line array are the main variables that govern the sound level output and coverage area of the line array. The height of an array governs the line array's directivity. The spacing of the individual speakers, which is a second-order effect, determines a lobing structure of the line array. For example, a relatively straight array may radiate the sound level desired for far field coverage. For near field coverage, the line arrays often require some degree of curvature to provide uniformity of coverage over a wider vertical angle.
Once a speaker arrangement for a given venue is determined, the speakers in the line arrays are then typically arranged and mounted on specially designed racks. Depending upon the desired arrangement, the line arrays are then suspended in the air with hanging equipment, which is referred to as a “tension” configuration herein and/or placed on the ground, which is referred to as a “compression” configuration herein. Additionally, support structure (e.g., chains) may be connected to speakers that are hung from the ceiling, such that the corresponding rigging systems are in compression. By arranging the line array speakers and articulating or curving the line array in the vertical plane at a specific splay angle, one can provide excellent coverage for listeners seated in both the near and the far fields.
U.S. Pat. No. 8,170,263 to Engebretson et al. discloses an example of a rigging system for line array speakers and allows for the adjustment of a splay angle between adjacent loudspeakers.